Green Active Wearable Printed Antennas for Medical Applications

Low-profile compact active and tunable antennas are needed in a number of communication systems. Printed antennas possess attractive features, such as being low profile, flexible, lightweight, with a small volume and low production cost. A microstrip antenna’s resonant frequency is altered due to environment conditions, different antenna locations and different system modes of operation. Wearable printed active and tunable antennas are not widely presented in the literature. However, microstrip antennas have been widely presented in books and papers in the last decade [ 1 – 7 ]. A new class of wideband active and tunable wearable antennas for medical applications is presented in this section. For example the antenna VSWR is better than 2:1 at 434 MHz + 5%. The antenna beam width is around 100°. The antenna’s gain is around 0 to 2 dBi. A voltage-controlled varactor is used to control the antenna resonant frequency at different locations on the human body. Amplifiers may be connected to the wearable antenna feed line to increase the system’s dynamic range.